In the last decade we have made significant progress in understanding the biochemical and biophysical aspects of the motility of cells in tissue culture. Our knowledge of cell motility within the embryo, however, has lagged behind. The techniques and perspectives that have been developed from tissue culture studies may now allow us to approach similar problems in the more complex environment of the living embryo. The purpose of this meeting is to bring together cell biologists, working on the cellular and molecular basis of motility, with developmental biologists, who have studied the morphogenetic behavior and patterns of migration within the embryo. Our goal is to stimulate productive interactions between these two groups of scientists. Many possible fruitful collaborations might emerge from such a meeting: for example, molecular engineering may be applied to cells that are involved in a morphogenetic process, or fluorescence-imaging, which has been perfected with tissue culture cells, might be applied to cells moving within an organism. Such a meeting would be unique in drawing together individuals who would not normally interact closely with each other.